let n be Element of NAT ; :: thesis: for C being connected compact non horizontal non vertical Subset of (TOP-REAL 2)
for i, j, k being Element of NAT st 1 <= i & i <= len (Gauge C,n) & 1 <= j & j <= k & k <= width (Gauge C,n) & (Gauge C,n) * i,j in L~ (Lower_Seq C,n) holds
ex j1 being Element of NAT st
( j <= j1 & j1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} )

let C be connected compact non horizontal non vertical Subset of (TOP-REAL 2); :: thesis: for i, j, k being Element of NAT st 1 <= i & i <= len (Gauge C,n) & 1 <= j & j <= k & k <= width (Gauge C,n) & (Gauge C,n) * i,j in L~ (Lower_Seq C,n) holds
ex j1 being Element of NAT st
( j <= j1 & j1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} )

let i, j, k be Element of NAT ; :: thesis: ( 1 <= i & i <= len (Gauge C,n) & 1 <= j & j <= k & k <= width (Gauge C,n) & (Gauge C,n) * i,j in L~ (Lower_Seq C,n) implies ex j1 being Element of NAT st
( j <= j1 & j1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} ) )

assume that
A1: 1 <= i and
A2: i <= len (Gauge C,n) and
A3: 1 <= j and
A4: j <= k and
A5: k <= width (Gauge C,n) and
A6: (Gauge C,n) * i,j in L~ (Lower_Seq C,n) ; :: thesis: ex j1 being Element of NAT st
( j <= j1 & j1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} )

set G = Gauge C,n;
A7: k >= 1 by A3, A4, XXREAL_0:2;
then A8: [i,k] in Indices (Gauge C,n) by A1, A2, A5, MATRIX_1:37;
set X = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n));
A9: (Gauge C,n) * i,j in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by RLTOPSP1:69;
then reconsider X1 = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) as non empty compact Subset of (TOP-REAL 2) by A6, XBOOLE_0:def 4;
A10: LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) meets L~ (Lower_Seq C,n) by A6, A9, XBOOLE_0:3;
set s = ((Gauge C,n) * i,1) `1 ;
set e = (Gauge C,n) * i,k;
set f = (Gauge C,n) * i,j;
set w2 = upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n))));
A11: j <= width (Gauge C,n) by A4, A5, XXREAL_0:2;
then [i,j] in Indices (Gauge C,n) by A1, A2, A3, MATRIX_1:37;
then consider j1 being Element of NAT such that
A12: j <= j1 and
A13: j1 <= k and
A14: ((Gauge C,n) * i,j1) `2 = upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))) by A4, A10, A8, JORDAN1F:2, JORDAN1G:5;
set q = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|;
A15: j1 <= width (Gauge C,n) by A5, A13, XXREAL_0:2;
A16: ((Gauge C,n) * i,k) `1 = ((Gauge C,n) * i,1) `1 by A1, A2, A5, A7, GOBOARD5:3;
then ((Gauge C,n) * i,j) `1 = ((Gauge C,n) * i,k) `1 by A1, A2, A3, A11, GOBOARD5:3;
then A17: LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) is vertical by SPPOL_1:37;
take j1 ; :: thesis: ( j <= j1 & j1 <= k & (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} )
thus ( j <= j1 & j1 <= k ) by A12, A13; :: thesis: (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)}
consider pp being set such that
A18: pp in N-most X1 by XBOOLE_0:def 1;
reconsider pp = pp as Point of (TOP-REAL 2) by A18;
A19: pp in (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) by A18, XBOOLE_0:def 4;
then A20: pp in L~ (Lower_Seq C,n) by XBOOLE_0:def 4;
A21: 1 <= j1 by A3, A12, XXREAL_0:2;
then A22: ((Gauge C,n) * i,j1) `1 = ((Gauge C,n) * i,1) `1 by A1, A2, A15, GOBOARD5:3;
then A23: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| = (Gauge C,n) * i,j1 by A14, EUCLID:57;
then A24: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `2 <= ((Gauge C,n) * i,k) `2 by A1, A2, A5, A13, A21, SPRECT_3:24;
A25: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `2 = N-bound ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n))) by A14, A23, SPRECT_1:50
.= (N-min ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))) `2 by EUCLID:56
.= pp `2 by A18, PSCOMP_1:98 ;
pp in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by A19, XBOOLE_0:def 4;
then pp `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `1 by A16, A22, A23, A17, SPPOL_1:64;
then A26: |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| in L~ (Lower_Seq C,n) by A20, A25, TOPREAL3:11;
for x being set holds
( x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| )
proof
let x be set ; :: thesis: ( x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) iff x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| )
thus ( x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) implies x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| ) :: thesis: ( x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| implies x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) )
proof
reconsider EE = (LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) as compact Subset of (TOP-REAL 2) ;
reconsider E0 = proj2 .: EE as compact Subset of REAL by JCT_MISC:24;
A27: (Gauge C,n) * i,k in LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by RLTOPSP1:69;
A28: ((Gauge C,n) * i,j) `2 <= |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `2 by A1, A2, A3, A12, A15, A23, SPRECT_3:24;
((Gauge C,n) * i,j) `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `1 by A1, A2, A3, A11, A22, A23, GOBOARD5:3;
then |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| in LSeg ((Gauge C,n) * i,k),((Gauge C,n) * i,j) by A16, A22, A23, A24, A28, GOBOARD7:8;
then A29: LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| c= LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k) by A27, TOPREAL1:12;
assume A30: x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) ; :: thesis: x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|
then reconsider pp = x as Point of (TOP-REAL 2) ;
A31: pp in LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| by A30, XBOOLE_0:def 4;
then A32: pp `2 >= |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `2 by A24, TOPREAL1:10;
pp in L~ (Lower_Seq C,n) by A30, XBOOLE_0:def 4;
then pp in EE by A31, A29, XBOOLE_0:def 4;
then proj2 . pp in E0 by FUNCT_2:43;
then A33: pp `2 in E0 by PSCOMP_1:def 29;
E0 is bounded by RCOMP_1:28;
then E0 is bounded_above by XXREAL_2:def 11;
then |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `2 >= pp `2 by A14, A23, A33, SEQ_4:def 4;
then A34: pp `2 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `2 by A32, XXREAL_0:1;
pp `1 = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| `1 by A16, A22, A23, A31, GOBOARD7:5;
hence x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| by A34, TOPREAL3:11; :: thesis: verum
end;
assume A35: x = |[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| ; :: thesis: x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n))
then x in LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]| by RLTOPSP1:69;
hence x in (LSeg ((Gauge C,n) * i,k),|[(((Gauge C,n) * i,1) `1 ),(upper_bound (proj2 .: ((LSeg ((Gauge C,n) * i,j),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)))))]|) /\ (L~ (Lower_Seq C,n)) by A26, A35, XBOOLE_0:def 4; :: thesis: verum
end;
hence (LSeg ((Gauge C,n) * i,j1),((Gauge C,n) * i,k)) /\ (L~ (Lower_Seq C,n)) = {((Gauge C,n) * i,j1)} by A23, TARSKI:def 1; :: thesis: verum